Electromagnetic Waves

by Kira Harvey

What kind of disturbance creates an electromagnetic wave?

Electromagnetic waves are produced by a vibrating electric charge. They have both an electric and a magnetic component.

How are electromagnetic waves different from mechanical waves?

For one, electromagnetic waves are able to travel through a vacuum - a region void of matter. Mechanical waves require a medium in order to propagate from one location to another.

What is the Electromagnetic Spectrum?

The electromagnetic spectrum is the range of wavelengths or frequencies over which electromagnetic radiation extends. For example, there are radio waves, microwaves, infrared, visible light, ultraviolet radiation, x-rays, and gamma rays.

Radio Waves

Radio waves are longer than 1 mm. Since these are the longest waves, they have the lowest energy and are associated with the lowest temperatures. These waves are used in radios and aircraft communication.

Microwaves

Infrared

Infrared wavelengths span from 710 nm – 1 millimeter (from the width of a pinpoint to the size of small plant seeds). At a temperature of 37 degrees C, our bodies give off infrared wavelengths with a peak intensity near 900 nm. Infrared is used in night vison goggles and in space it helps us map the dust between stars.

Visible Light

Visible light covers the range of wavelengths from 400 – 700 nm (from the size of a molecule to a protozoan). Our sun emits the most of its radiation in the visible range, which our eyes perceive as the colors of the rainbow. Light bulbs and rainbows are example of visible light.

Ultraviolet Radiation

Ultraviolet radiation has wavelengths of 10 – 310 nm (about the size of a virus). Ultraviolet radiation comes from the sun and is used in tanning beds.

X-Ray

X-rays range in wavelength from 0.01 – 10 nm (about the size of an atom) and are used to take X-Rays. Air port security also uses them to scan people.

Gamma Ray

Gamma rays have the shortest wavelengths, < 0.01 nanometers (about the size of an atomic nucleus). This is the highest frequency and most energetic region of the electromagnetic spectrum. They are used by doctors to see inside of the body and black holes.

Electromagnetic Spectrum Song